Citing a public health concern over antimicrobial-resistant bacteria, the Food and Drug Administration today announced a plan to phase out the use of antibiotics in livestock feed to promote animal growth.

The FDA has called on animal pharmaceutical companies to voluntarily change the labels on antibiotic feed products, eliminating their FDA-approved use as a growth promoter, officials said. Once the labels change, it would become illegal to feed these antibiotics to animals without the approval of a veterinarian for a medical purpose.
Companies have 90 days to tell the FDA they will comply with the plan, and then they'll be given three years to transition away from antibiotic feed. Only antibiotics that affect human illnesses apply.

"We believe this is a major step forward in helping make sure important antibiotics maintain their efficiency for the future," Michael Taylor, the FDA's deputy commissioner for foods and veterinary medicine, said during a press conference.

Currently, up to 70 percent of the antibiotics sold in the United States are given to healthy food animals, according to Pew Charitable Trusts, a nonprofit think tank.

Although it is voluntary, Taylor said the FDA will take regulatory action against those not participating. He said two of the largest animal pharmaceutical companies have already agreed to change their labels.

"We have a high confidence that this approach will succeed," Taylor said.

But not everyone is so sure.

Researchers at Johns Hopkins Center for a Livable Future say the plan will not change the way these drugs are used in food animals because there's a loophole. Animals consume low doses of antibiotics over long stretches of time for both growth promotion and disease prevention. Using them in healthy animals for disease prevention is still allowed, meaning they could still be used for growth promotion and contribute to antibiotic resistant bacteria.

"Whether you call it growth promotion or disease prevention, this makes antibiotics less effective for treating sick people," said Keeve Nachman, a scientist with the Johns Hopkins Bloomberg School of Public Health's Department of Environmental Health Sciences and Health Policy and Management.

Rep. Louise Slaughter (D-NY), the only microbiologist in Congress, said the plan is an "inadequate" response to the antibiotic-resistant bacteria crisis stemming from livestock feed because the FDA has no mechanism to enforce it. She has authored her own legislation, the Preservation of Antibiotics for Medical Treatment Act, which would make a ban on antibiotic use in healthy animals mandatory, but companies lobbied heavily against it. It did not pass.

"Sadly, this guidance is the biggest step the FDA has taken in a generation to combat the overuse of antibiotics in corporate agriculture, and it falls woefully short of what is needed to address a public health crisis," Slaughter said in a statement.

Still, Dr. William Schaffner, chairman of preventive medicine at Vanderbilt University Medical Center in Nashville, Tenn., said this is an important step forward for the United States, considering that Europe enacted a similar ban in 2006, and it's been shown to work without hurting the meat and poultry business.

In labs, Schaffner said researchers expose bacteria to low doses of antibiotics over time when they want to create antibiotic resistant bacteria, and this is similar to what is happening in food animals' digestive systems.

"In effect, all of these animals have been just like a test tube in which we have been creating resistant bacteria," he said. "They then go to the slaughterhouse. Slaughterhouses are not very hygienic places as you can imagine. The meat products that we get become contaminated with the bacteria that were in the animals."

He said the bacteria is then passed to humans, who accidentally contaminate counters or undercook their food.

"That chain has been demonstrated," Schaffner said, adding that public health officials have been pushing for a ban on antibiotics for livestock growth in the United States for years. "I think this is a good thing. It's not perfect, but it is another good step toward better public health."